CoW, cosinor on the web is an easy to use web-based application. Its purpose is to help (mainly) students estimate presence of 24-h periods in their time-stamped data.
Cosinor [Cosine vector] n. A procedure for the analysis of biological rhythms based on the plotting of a cosine wave to the raw data. Note: The singlecosinor procedure plots a single cosine function with a presumed period (anticipated on the basis of prior experience) to the time series and provides estimates of mesor, amplitude, and acrophase. More complex cosinor procedures utilize a fundamental function and one or more harmonics.